Tuesday, October 26, 2010

I cannot find any heat stroke guidelines for warm water so let's 'crowd source' this and come up with our own.

I have always said that the readers of my blog are smarter and better informed than I am, how about we deduce what the safe water temperature for a 10k-swim should be?

I figured the Navy would be the place to look for info on heat stroke and warm water deaths but I could not find anything. Consequently it is my belief that we have to use FINA's maximum pool temp as a benchmark but then minus 7-degrees from that temp as an ad hoc, temporary, benchmark.

Here is why: I learned that saltwater is more "insulated" so to speak than fresh water for ocean water will only freeze at 25-degrees Fahrenheit versus the 32-degrees Fahrenheit needed for "normal" water to freeze.

My deduction, based on this benchmark, is that ocean water feels 7-degrees warmer than fresh water. Ergo, by deducting 7-degrees off the FINA 82-degree maximum pool temperature benchmark; (No one has died of heatstroke in a pool), and make a bold statement that swimming in 75-degree water should be safe in sub 90-degree temps. We have a safe rule for swimmers to use when asked to compete in sketchy conditions.

Please correct me if I am wrong.


Bill Ireland said...

You've asked a good question, which is really two questions--what is optimal for comfort and or performance and what is unsafe. Also, what about individual susceptibility. We all know swimmers who are better at cold water swimming. And others who are worse. I'm good at cold water and not so good at warm water. I've swum in 53 degrees cold and been OK. I've swum in 84-85 warm and been OK but been pretty uncomfortable. I have friends who would fall to pieces at less than 62 but have been ok in 84-85 degree water. For comfort I would go for 66 to 80. For safety, I would probably go from 58 to 83. I'd be hesitant about a big competion outside that range.

Having said that, I don't know where I would put the upper limit.

Anonymous said...

Hey Tony, I live in Southern Florida where ocean and pool water routinely gets into the high 80's and low 90's during the summer months. My experience is that 84-85 degree water still feels cooler then body temperature but when you get to 88-89 it starts to feel like a bath. Skin temp IIRC is 94 degrees but 88-89 water feels like body temp. There is a big transition in feeling when you go from 85 to 89. I'm not a swimmer, but for me I would not want to exert myself in water above 85 degrees.


Tony Austin said...

The Navy has a chart that if you are in water that is 80-degrees plus, you will survive and not get hypothermia. 50-60 degree water is something like 1-6 hours.

Since we cool with evaporative cooling; (air cooling off sweat), when does the heat of the water act as an insulating factor? What temperature deficit do we need between the heat being generated by the body versus the temp in the water to cool it?

One reader who has several patents with his name on it with CitiBank; Fred P. says the formula is out there in a thermodynamics book but he couldn't remember.

danthefiddleman said...

Interesting take on it here from a doctor who also swims. "Having a 10K (2 hour) race in 86 degree water," he says, "is criminal."

Tony Austin said...

How bad can our governing bodies get?

LC said...

My concern is that this will become a pendulum that swings the other way instead of improving safety we will say 'it is too hot/cold to swim'

In this hot water the safety talk should emphasis heat stroke/exhaustion and the proper hydration.

There should have been more lifeguards deployed and rescue craft. They should have been schooled on heat exhaustion and what to watch for. They should have responded to anything they saw that was worrisome.

There should have been 'people counting' in and out of the water and during the race at every buoy and between.

Never should an athlete (young lady) have to raise her hand for assistance and not come.

Due to the high heat both air/water extra hydration stations should have been employed.

And the USA should have had a Open Water coach or two not just a parent there to reinforce the hydration, heat exhaustion/stroke symptoms.

This tragedy was avoidable but not because it was unswim-able but because proper safety concerns and precautions were not taken and implemented.

Tony Austin said...

Everything you say would have worked. Nobody would have died!

Remember, the evaporative cooling element that our bodies employ also was a fail.

Yes, Hydration played an issue but so did core temperature. Turns out you cannot die of exhaustion unless you pass out in an ocean or next to a cliff.

Also, our bodies cool via evaporative cooling but when the body is submerged in hot liquid, cooling cannot take place.

Fran Crippen most likely went hyperthermic.

Thanks for your observations.

I am about to publish a doctor's opinion.